As an example of a lens barrel, an interchangeable camera lens is well known in the art, which is provided with two actuators for moving two sets of lens groups in the direction of the optical axis (see for example Jpn. Pat. Appln. KOKAI Publication No. 2000-14750). Each of the two actuators is a voice coil motor (VCM) including: a coil that is fixed to a movable member that holds a lens group; a magnet fixed to an outer frame and opposed to the coil; and a yoke for forming a magnetic circuit.
When a current flows to the coil of the VCM, the movable member moves along the yoke in the direction of the optical axis by electromagnetic induction.
In the state where no current is supplied to the coil, however, the movable member can freely move along the yoke. For this reason, a partitioning plate has to be provided between two movable members.
If the coil is movable with respect to the yoke, light may undesirably travel through a gap between the coil and the yoke. Such light does not sequentially travel through the two lens groups and has adverse effects on the images photographed by the camera.
The present invention has been made in consideration of the above, and is intended to provide a lens barrel which prevents lenses from colliding with each other in the non-current supply mode, and which provides reliable optical characteristics in the current supply mode.